On Thu, Nov 6, 2014 at 12:45 PM, Stefan van Zwam <[email protected]> wrote: > It does, and must be a bug. It involves hashing, so in the worst case it’s a > Python or Cython bug. > > For the time being, convert everything to binary matroids before doing a > membership test like that.
That will avoid the issue then? D. > —Stefan. > > On Nov 5, 2014, at 4:54 PM, Dillon Mayhew <[email protected]> wrote: > >> Right, so the weak_invariant is not acting as an invariant on >> isomorphism classes? Doesn't that have an effect on the general >> isomorphism test (not just within the regular matroid type)? >> >> D. >> >> On Thu, Nov 6, 2014 at 3:24 AM, Stefan van Zwam <[email protected]> >> wrote: >>> The problem seems to be in the _weak_invariant() method: if N is as defined >>> below, and M is the matroid in the catalog, we get: >>> >>> sage: (N._weak_invariant(), M._weak_invariant()) >>> (-7774345140401701701, -4449946732485601636) >>> >>> That's when the isomorphism test decides these guys are different. >>> >>> --Stefan >>> >>> -- >>> >>> --- >>> You received this message because you are subscribed to the Google Groups >>> "sage-matroid" group. >>> To unsubscribe from this group and stop receiving emails from it, send an >>> email to [email protected]. >>> For more options, visit https://groups.google.com/d/optout. >> >> -- >> >> --- >> You received this message because you are subscribed to the Google Groups >> "sage-matroid" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> For more options, visit https://groups.google.com/d/optout. > > -- > > --- > You received this message because you are subscribed to the Google Groups > "sage-matroid" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. -- --- You received this message because you are subscribed to the Google Groups "sage-matroid" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
